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The evidence basis needed for developing screening policies and implementing screening programmes, including established programmes such as breast and cervix and those currently in development, being piloted or subject to major research activity

Health Technology Assessment

Health technology assessment (HTA) uses evidence to promote health and prevent and treat disease. HTA includes the implication of heath technology to improve health outcomes. It asks whether technology provides benefits for the population and if it presents value for money.

The evidence basis for screening is whether early detection is beneficial, and if persons identified with early-state disease detected through screening have better health outcomes than those who come to clinical attention without screening. It is not enough to know that a screening test actually identifies early diseases or conditions at a specific point of disease development. There must also be an effective intervention, which itself must be scientifically assessed.

The evidence to support or refute particular screening programmes is often limited. This may be because of the complexity of the screening issue, or the rarity of the conditions being screened for. The best evidence for screening comes from randomised controlled trials (or meta-analysis of RCTs). The UK NSC then assesses this evidence against the criteria for appraising the viability, effectiveness and appropriateness of a screening programme (see “Evaluating screening programmes”).

A regular review when the current recommendation is not to offer population screening is due

A regular review when the current recommendation is to offer population screening

When new evidence is published which brings into question a current recommendation on screening

When a proposal is made to modify, or make big changes to, a current screening programme

When a proposal for a new topic which has not been previously reviewed by the UK NSC is submitted.

Figure 3.9.1 below shows the overall UK NSC evidence review process. The aim of the process is to ensure that each topic is addressed in a proportionate manner and to provide reassurance to stakeholders that decisions are grounded in, and informed by, up to date evidence.